Traxxas Revo 3.3

HELP.... My son has the Revo and it use to idol in place. Now when we start it it wants to take off. Its not bad but if you pick it up it will run but as soon as you put pressure on the wheels it dies. Now if you give it gas it will run/go but as soon as you let off the gas and it comes close to a stop it dies again.. Can someone advise please....

it being to lean or rich very well could be a problem... i have a revo 3.3 my self... not to long after i bought my revo the clutch spring broke on my revo, which caused it to not sit and idol in one spot... you need the clutch spring to hold the clutch shoes back from gripping the clutch bell and thats why it can sit and idol in one spot, when you give it gas(with a properly working clutch spring) the shoes will fling out and grab the clutch bell which is attached to the pinion gear... so you may have a broke clutch spring... if i remember right the spring came with the shoes and it was abot $8...the only way to confirm its the clutch spring is to remove the engine and take the clutch bell off and soo if the spring is still in tact.